The string-pulling paradigm has been adapted to investigate many psychological phenomena across a range of animal species. Although varying string length has been shown to influence performance, the nature of the representation remains to be determined. Across three experiments, rats were shaped to pull string to receive food reinforcement. Either string length or reinforcement rate was manipulated to examine the influence on string-pulling behavior. Experiment 1 demonstrated that varied string length was sufficient to elicit an odor discrimination. Subsequent experiments provided evidence that varying string length (Experiment 2) and reinforcement rate (Experiment 3) produced qualitatively distinct patterns of string-pulling behavior. In Experiment 2 rats that received a long string were more likely to pull in the probe string to the end, yet no differences were observed in approach time between short and long groups. However, in Experiment 3 rats that received low reinforcement were less likely to pull in the probe string to the end and were slower to approach the string to begin pulling. These results are consistent with rats using temporal and motivational characteristics to guide responding during string-pulling behavior.

中文翻译：

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字符串长度对大鼠拉弦行为组织的影响。

拉弦范例已被改编为研究多种动物物种的许多心理现象。尽管已显示变化的字符串长度会影响性能，但是表示的性质仍有待确定。在三个实验中，大鼠被塑造成拉绳状以接受食物强化。操纵弦长或加固率以检查对弦拉行为的影响。实验1表明，变化的弦长足以引起气味辨别。随后的实验提供了证据，证明不同的弦长（实验2）和增强速率（实验3）产生了定性不同的拉弦行为模式。在实验2中，收到长绳的大鼠更有可能将探针绳拉到末端，然而，短组和长组的进场时间没有差异。但是，在实验3中，受力较小的大鼠不太可能将探针绳拉到末端，并且较慢地接近探针绳以开始拉绳。这些结果与大鼠使用时间和动机特征来指导拉弦行为时的反应是一致的。